The entertainment industry is in the midst of a digital revolution. Music, television, and movies are increasingly becoming digital, offering new advantages to the consumer in quality and flexibility. At the same time the digital revolution also comprises a threat since digital data can be perfectly and quickly copied. If consumers may freely copy entertainment content and offer that content on the Internet, the market for entertainment content would evaporate.
The rapid growth in the distribution of digital content over the Internet, such as MP3s and DivX encoded movies, is especially alarming to content owners. These highly controversial and unauthorized distribution channels have caused an increase in demand from the entertainment industry for methods to protect their multi-million dollar content. Developing a content protection system that offers content owners an end-to-end solution they can use to securely distribute their copyrighted content is becoming increasingly important as the amount of content shared across the Internet grows exponentially each year.
One conventional approach for distribution of electronic content over a network infrastructure uses prepaid media (reference is made to U.S. Pat. No. 6,434,535 B1). A user obtains a prepaid media that comprises a unique key. The user contacts a specified server with the unique key and a remaining balance of the prepaid media. If the media and the remaining balance are valid, the user can download to the media a selected item of protected content that has been encrypted with the unique key. However, this approach does not allow a user to obtain the protected content from sources other than the specified server nor does this approach provide a method for a user to obtain authorization to use an item of protected content obtained through an unauthorized source.
Recently, developments in consumer electronics have created an alternative to traditional digital rights management systems. New recording and playing devices that use this new method, known as CPRM (Content Protection for Recordable Media) technology, have reached the market. It is now possible to directly record content protected in CPRM to writable media. If the recording is prepared in a server, the client needs no special keys or tamper-resistance. This method of content protection utilizes broadcast encryption. Devices do not need to have a conversation to establish a common key. Recent advances in broadcast encryption have made it as powerful as public-key cryptography in terms of revocation power. Because of its one-way nature, broadcast encryption is inherently suited to protect content on storage.
Once the client receives the encrypted content using CPRM, the interaction between the content server and the client side module is complete. The server is now free to focus on other requests. On the client side, CPRM requires that the encrypted content be recorded onto a physical piece of media, such as a recordable optical disk. This recording is performed in such a way that the encrypted content can only be played by a compliant device while it is on that particular piece of media. Consequently, encrypted content copied to another physical piece of media cannot by played by a compliant device.
CPRM devices use the media key block and media ID located currently on blank DVD recordable disks to calculate a media unique key. The media unique key is used to encrypt title keys. In turn, the title keys encrypt the content stored on the DVDs. Encrypting the title keys in the media unique key causes the title keys to become cryptographically bound to the particular piece of physical media on which the content is burnt. This prevents the encrypted content from being decrypted and accessed from any other physical piece of media.
Although this technology has proven to be useful, it is desirable to present additional improvements. Conventional techniques for copy protection of protected content prevent the use of protected content through superdistribution, i.e., file-sharing. For example, a user has a licensed copy of a protected content such as a movie on a DVD. The user shares the content with another user such as a friend over the Internet. The friend copies the content to a protected media such as a DVD-RAM. Conventional copy protection techniques prevent the friend from playing the content. However, conventional copy protection techniques do not allow the friend to purchase a license for use of the acquired content. By limiting the response of the protected media to “do not play”, conventional copy protection techniques limit the sale of protected content through channels such as superdistribution.
What is therefore needed is a system, a service, a computer program product, and an associated method for enabling consumers to distribute protected content using protected media in a secure and legitimate fashion. The need for such a solution has heretofore remained unsatisfied.